Re: BUG #18297: Error when adding a column to a parent table with complex inheritance - Mailing list pgsql-bugs

From Tender Wang
Subject Re: BUG #18297: Error when adding a column to a parent table with complex inheritance
Date
Msg-id CAHewXN=dPJDvaoME0G9vyemUmY-TpDuqQfcHJRWfUvSWX1p=rQ@mail.gmail.com
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In response to Re: BUG #18297: Error when adding a column to a parent table with complex inheritance  (Alexander Lakhin <exclusion@gmail.com>)
Responses Re: BUG #18297: Error when adding a column to a parent table with complex inheritance
List pgsql-bugs

Alexander Lakhin <exclusion@gmail.com> 于2024年1月18日周四 17:00写道:
Hello Tender Wang and Richard,

17.01.2024 18:03, Tender Wang wrote:
Thanks for reviewing the patch.
The attached v2 patch includes all review advices.

--
Tender Wang
OpenPie:  https://en.openpie.com/

Richard Guo <guofenglinux@gmail.com> 于2024年1月17日周三 19:54写道:

Indeed.  We may update the same child column multiple times, but there
is no CommandCounterIncrement between.  Nice catch and +1 to the fix.

To nitpick, how about go with the comment as

    /* Make sure the child column change is visible */

which seems clearer.

Also I think it'd be better to include a blank line before and after the
new CommandCounterIncrement statement.

Also I suggest to drop the new added tables after we've run ALTER TABLE
in the test case.

Thanks
Richard

Thank you for working on this!

(Maybe it's possible to slightly modify an existing hierarchy with tables
a, b, c in inherit.sql for the purpose of the check added.)

I've found another situation where the same error is produced:
CREATE ROLE u;
DROP ROLE u, u;
ERROR:  tuple already updated by self

Indeed, but this issue cann't simply calling CommandCounterIncrement() to fix.
It will report "could not find tuple for role" if we simply calling CommandCounterIncrement() when drop seond 'u'.

I think we can sort the role_addresses list and skip the same role id. I don't intend to fix above two issues in one patch.
So I add a new 0001 attached patch.


Perhaps, you would like to fix it in passing too. I've rechecked all the
other object types, that can be DROPped with a list (namely, AGGREGATE,
DOMAIN, EXTENSION, FOREIGN DATA WRAPPER, FOREIGN TABLE, FUNCTION, INDEX,
MATERIALIZED VIEW, OPERATOR, PROCEDURE, ROUTINE, SEQUENCE, SERVER,
STATISTICS, TABLE, TYPE, VIEW), and found that all of these handle
such duplicate entries with no error.

I'm not sure if there are other problems like this.
 
Best regards,
Alexander
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